a) Field of the Invention
The invention concerns a traction device for vehicles having at least one ground engaging tire. In particular, the invention is directed to an emergency traction device which is readily fitted to tires of various diameters and widths.
b) Description of Related Art
Known traction devices include snow tires, studded tires, and tire chains. The use of snow or studded tires require that the vehicle operator anticipate the occurrence of inclement weather and replace the ordinary tires with the snow or studded tires. Consequently, two sets of tires are required which must either be alternately mounted on one set of vehicle wheels, or a second set of wheels must be obtained. Disadvantages of snow or studded tires include the cost of changing multiple set of wheels and/or tires, and the inability to react to unexpected weather.
Tire chains are commonly installed on the ordinary tires of a vehicle to enable an operator to react to, rather than anticipate, inclement whether. The disadvantages of tire chains include the need to have a set of chains sized to fit the particular tires of a vehicle, and the possibility of a chain being "thrown-off" a rotating wheel damaging the vehicle body. Further, tire chains are generally installed by driving a tire onto the chain and subsequently linking the chain around the circumference of the tire. In the event the vehicle is already stuck, i.e. the tire spins without gaining traction, it is not possible to install the chains which could free the vehicle without elevating the tire off the ground.
U.S. Pat. No. 5,735,980 to Robeson discloses an emergency traction device in which the mechanisms for fitting the device to the diameter and width of the wheel each include a separate winch.
Other types of device intended to be attached to the tires and/or wheels of vehicles for the purpose of improving traction are described in the United States Patents to Laub (U.S. Pat. No. 5,513,684); Metraux (U.S. Pat. No. 5,254,187); Zelent (U.S. Pat. No. 4,974,653); Parker, III (U.S. Pat. No. 4,886,100); McDonough (U.S. Pat. No. 4,862,936); Regensburger (U.S. Pat. No. 4,209,049); Hyggen (U.S. Pat. Nos. 4,122,880 and 3,891,018); Welsh (U.S. Pat. No. 4,098,314); Gomez (U.S. Pat. No. 3,847,196); Clark (U.S. Pat. No. 3,736,970); Scott (U.S. Pat. No. 3,249,143); Bopst III (U.S. Pat. No. 3,053,302); Hayes (U.S. Pat. No. 2,981,303); Binegar (U.S. Pat. No. 2,910,105); Schroen (U.S. Pat. No. 2,640,522); Pindjak (U.S. Pat. No. 2,598,298) and Edwards (U.S. Pat. No. 2,423,759). In general, these patents disclose traction devices having a plurality of arms extending outward toward the tread surface of the tire.